Electromagnetic relay



u 1942- c. w. KUHN ETAL 2,234,521

ELECTROMAGNETIC RELAY Filed May 4. 1939 STATES UNITED PATENT OFFICE ELECTROMAGNETIC RELAY Clarence W. Kuhn, Wauwatosa, Theodore F. Rosing, Whitefish Bay, and William 0. Stevens, Milwaukee, Wis., assignors to Cutler-Hammer, Inc., Milwaukee, Wis., a corporation of Delaware Applicatimi May 4, 1939, Serial No. 271,730

8 Claims.

This invention relates to electromagnetic relays and while not limited thereto is particularly adapted to alternating current relays which are to be operated with a minimum of electrical energy for their energizing circuit.

An object of the invention is to provide an improved relay which is reliable and positive in operation.

Another object is to provide a relay which When deenergized positively releases its armature.

Another object is to provide a novel method of securing the energizing coil of a relay so as to be rigidly held in place without any additional special parts for its securement.

Another object is to provide a simple and reliable bearing having a minimum of friction for the armature of a relay.

Another object is to provide a relay which may be easily adapted for the commutation of a variety of circuits.

Another object is to provide a simple guide for the rectilinear movement of the movable contacts of a relay, while the same are actuated by a pivoted rotating armature.

Another object is to provide a relay which is simple in construction and operation and easily assembled and adjusted and with a minimum of skill.

Other objects and advantages will hereinafter The accompanying drawing is illustrative of a relay embodying the invention.

In the drawing,

Figure 1 is a front view of the relay.

Fig. 2 is a section along 2-2 of Fig. 1.

Fig. 3 is a section along 3--3 of Fig. 1.

Fig. 4 is a bottom view of a device similar to Fig. 1, but including a modified contact arrangement and including a magnet to adapt the device for use with direct current, and

Fig. 5 is a section along 5-5 of Fig. 4.

Referring to the drawing, i represents a moulded base of insulation which is suitably shaped to receive the various parts of the relay and insulate them from each other where required and also to permit their assembly with the base into a unitary structure. Mounted on the base is a magnet frame 2 fashioned of a strip of magnetic material and having two limbs 3 and 4 arranged at right angles to each other, the limb 3 lying flat against the upper face of the base I. Mounted on the limb 3 and perpendicular thereto is a magnet core 5 held in place by a cap screw 6 which is threaded into the lower end of the core 5 and which passes through alined clearance holes 1 and 8 in the limb 3 and the base I respectively, so as to also fasten the frame 2 to the base I. To insure against any possible movement of frame 2 relative to base I, I prefer to provide a hollow eyelet 4| which penetrates alined openings in base I and limb 3 of the frame and has the shank end thereof upset, as shown in Fig. 3. The upper end of the core 5 is provided with a transverse slot 9 which divides said end into two areas one of which is embraced by a number of like shading coils ill. The shading coils are assembled with the core into a unitary structure by soldering the parts together. Thus the sectors of the shading coils outside of the slot 9 form a head for the core 5 which is adapted to secure an energizing coil H to said core and tr prevent it from sliding on said core in a longitudinal direction, while the coil II is securec' against rotation on the core by an end flange H which is integral with the coil at the inner fact thereof and which abuts the inside of the liml 4 of the frame 2.

The limb 4 is provided near its outer end at it: lateral edges with upstanding brackets or ears it each having a slot therein which provides a1 open pivotal bearing for the armature M of thi I elay. To prevent retention of the armature ii fits attracted position due to residual magnetism 30; a non-magnetic gap is interposed by making th armature ll of a fiat strip of composite material the outer side thereof being ferromagnetic, whil' {the inside is a thin layer of non-magnetic ma terial such as certain alloys of stainless or bronz steel. The two layers are welded together durin; the rolling of the strip or sheet from which th armature is made. The non-magnetic layer i of such thickness that it interposes the lowes possible reluctance into the magnetic circui which will assure reliable release of the armaturt This thickness is of the order of three thou sandths of an inch and is too thick to be pro duced economically and with uniformity b electroplating and too thin to be molded o soldered to the ferromagnetic layer. The arma ture comprises two limbs l5 and IE which ar bent at a substantially right angle to each othe: A pin I1 is welded or otherwise fastened to th limb l6 near the bend of the armature to ion a trunnion for the armature adapted to engag the bearings in the ears l3. A stud I8 is rivete to the limb 4 of the magnet frame intermediate the ears l3 and the bend of the frame 2. Th stud l8 passes through a hole in the armatui and is threaded at its outer end to receive an ad justing nut 9. A spring 20 is interposed between the nut I9 and the armature to normally bias the latter away from the core -a bushing or washer 42 being preferably employed to provide an abutment for the upper end of spring 20 and to provide a proper bearing surface for engagement with the bosses or extrusions 43 formed on limb |6 of said armature. By adjusting the nut l9 and thus the tension of the spring 20 the biasing force can be varied.

The armature is adapted to actuate a bridging conductor or contact bar 2| which has its center supported by a bushing 22. The upper end of the bushing 22 is provided with a flange which limits the upward movement of the bar relative thereto, while the bar is loosely fitted to the bushing so as to permit a limited rocking motion of the bar, to facilitate adjustment of the cooperating contacts relative to each other and equalization of the contact pressure. The limb l6 has its outer end forked and preferably provided with a cylindrical surface which engages the lower surface of the bar 2|. The bushing 22 is s idable on a pin 23 riveted to the magnet frame limb 4 so as to provide for a rectilinear movement of the bar 2|. A second bushing 24 is slidably mounted on the first bushing 22. The bushing 24 is provided with a collar 25 which engages the lower face of the armature lever opposite the engagement thereof by the bar 2|. The bushing 22 has its outer end threaded to receive an adjusting nut 26 for the adjustment of a spring 21 interposed between said nut and the collar 25. The spring 21 cooperates with the spring 20 to bias the armature and to provide contact pressure for the bar 2|. Bar 2| is prevented from substantial rotary displacement with reference to bushing 22 and pin 2| by the provision of two ribs or ridges 28 on the insulating base as best illustrated in Fig. 3. The nuts l9 and 26 may be permanently secured to the respective studs by soldering after adjustment of the relay.

As shown in Figs. 1 and 2 the relay is provided with two sets of stationary contacts 29 and 30, respectively. The contacts 29 are bridged by the bar 2| which is provided with cooperating contact buttons 3|, when the relay is deenergized and the armature is biased away from the core 5, while the bar bridges the contacts 30 when the armature is in the attracted position. In this manner the pressure of the spring 20 biases the bar 2| against the flange of the bushing 22 and when the contacts 3| engage the contacts 30 the degree of compression of the spring 21 is increased (due to downward movement of bushing 24 relatively to bushing 22) to thereby produce the necessary contact pressure between the stationary and movable contacts 30 and 3| and also to amplify the bias acting on limb l6 of the armature as a result of the pressure of the spring 20. The stationary contacts are each mounted on an angle shaped strip 31 which is screw-fastened to the base and which is provided with a terminal screw 32 for the connection of circuit conductors.

In the modification shown in Figs. 4 and 5, the normally closed contacts 29 and their associated terminal plates 31 are omitted. In this modification adjustment of the air gap between the armature l4 and the core 5 is provided for by washers 33 shown in Fig. 3, which may be interposed between the bushing 22 and the limb 4 of frame 2. Furthermore, as shown in Figs. 4

and 5, if the contacts 29 are omitted, the contact buttons 38 are connected, through plates 39 carricd on insulating cross bar 40, with stationary terminals 34 by means of flexible leads 35each having one end welded or otherwise attached to a terminal plate 34 and the other end similarly attached to a plate 39, to thereby provide for completion of a circuit between the sets of terminals 34 and 31 when the relay is energized and the contact buttons 38 engage the buttons 30.

If the relay is employed to control a direct our- JO rent circuit it is frequently desirable to provide for a magnetic field at the contacts to facilitate the extinguishment of an are which may form upon opening of the circuit. In this case a horseshoe type permanent magnet 36 may be mounted at right angles to the base and intermediate of the contacts 30, as shown in Fig. 4, so that the poles of said magnet are located adjacent the contacts.

What we claim as new and desire to secure by Letters Patent is:

1. In an electromagnetic relay, a contact carrier, a stationary post, a sleeve slidable on said post affording a sliding support for said carrier and limiting its movement thereon in one direction, an operating member comprising an armature associated with said electromagnet and engaging said carrier and adapted to move it in said one direction, a second sleeve surrounding said first sleeve and adapted to engage said op crating member, and a biasing spring interposed between said sleeves and adapted to bias said second sleeve in said one direction.

2. In an electromagnetic relay, a contact carrier, a stationary post, a sleeve slidable on said post affording a sliding support for said carrier and limiting its movement thereon in one direction, an operating member comprising an armature associated with said electromagnet and engaging said carrier and adapted to move it in said 40 one direction, a second sleeve, surrounding said first sleeve and adapted to engage said operating member, a biasing spring interposed between said sleeves and adapted to bias said second sleeve in said one direction, an open pivotal bearing and 5 a cooperating pivot pin for said operating member, and associated means to insure contact between said bearing and said pin.

3. In an electromagnetic relay, a contact carrier, a stationary post, a sleeve slidable on said post afiording a sliding support for said carrier m cooperating pivot pin for said operating member,

a second post arranged intermediate of said bearing and said first post, and an adjustable spring interposed between said operatingmember and saidsecond post and affording contact between sa' bearing and said pin.

4. In an electromagnetic relay, in combination,

a inagnet core, an energizing coil surrounding said core, an L-shaped magnet frame partially surrounding said coil and affording a support for said core and forming therewith a magnetic circuit having an air gap, an armature bridging said air gap, said armature comprising a rolled bimetallic strip including a layer of ferromagnetic material and a layer of non-magnetic material welded integrally to the former and facing said core, a downwardly opening pivotal bearing for said armature attached to the lower surface of the horizontal portion of said frame and providing for oscillation of said armature relatively to said frame, biasing means including a coiled compression spring acting to bias said armature away from said core and to maintain contact between said armature and said bearing, a stationary contact, a movable contact adapted to engage said stationary contact, a stationary post rigidly attached to and depending from the hori' zontal portion of said frame upon which said movable contact is slidably mounted, means providing a positive driving connection between said movable contact and said armature in one direction of movement of the latter, and means providing a resilient driving connection between said parts in the opposite direction of movement of said armature, said last mentioned means including a coiled compression spring underlying said armature and said movable contact.

5. In an electromagnetic relay, in combination, a magnet core, an energizing coil surrounding "said core, an L-shaped magnet frame partially surrounding said coil and forming with said core a magnetic circuit having an air gap, an armature for bridging said air gap, said armature comprising a rolled bimetallic strip including a layer of ferromagnetic material and a layer of nonmagnetic material welded integrally to the former and facing said core, a downwardly opening pivotal bearing mounted upon the lower surface of the horizontal portion of said frame and a cooperating pivot pin on said armature adapted to permit oscillation of the latter in response to changes in excitation of said magnetic circuit, cooperating stationary and movable contacts, a carrier for said movable contact, a stationary post attached to and depending from the horizontal portion of said frame and a sleeve slidable on said post affording sliding support for said carrier and adapted to limit its movement thereon in one direction, a connection between said armature and said carrier affording operation of the latter by the former in said one direction, a second sleeve surrounding said first sleeve and adapted to engage said armature, a biasing spring interposed between said sleeves and adapted to bias said second sleeve in said one direction, a second post attached to and depending from said horizontal portion of the frame intermediate of said bearing and said first post, and an adjustable spring interposed between said armature and said second post and normally insuring contill tact between said pivot pin and said bearing and biasing of said armature away from said core, said first mentioned spring providing a resilient driving connection between said armature and said carrier during movement of the armature to its attracted position.

6. In a device of the character described, in combination, a contact carrier, a stationary post, a sleeve slidable on said post affording a sliding support for said carrier and limiting its movement thereon in one direction, an operating member engaging said carrier and adapted to move it in said one direction, a second sleeve surrounding said first sleeve and adapted to engage said operating member, and a biasing spring interposed between said sleeves and adapted to bias said second sleeve in said one direction.

7. In a device of the character described, in combination, a contact carrier, a stationary post, a sleeve slidable on said post affording a sliding support for said carrier and limiting its movement thereon in one direction, an operating member engaging said carrier and adapted to move it in said one direction, a second sleeve surrounding said first sleeve and adapted to engage said operating member, a biasing spring interposed between said sleeves and adapted to bias said second sleeve in said one direction, an open pivotal bearing and a cooperating pivot pin for said operating member, and associated means to insure contact between said pin and said bearing 8. In a device of the character described, in

combination, a contact carrier, a stationary post,

a sleeve slidable on said post affording a sliding support for said carrier and limiting its movement thereon in one direction, an operating member engaging said carrier and adapted to move it in said one direction, a second sleeve surrounding said first sleeve and adapted to engage said operating member, a biasing spring interposed between said sleeves and adapted to bias said second sleeve in said one direction, an open pivotal bearing and a cooperating pivot pin for said operating member, a second post arranged intermediate of said bearing and said first post and an adjustable spring interposed between saiC operating member and said second post and affording contact between said pivot pin and saic bearing.

CLARENCE W. KUHN.

THEODORE F. ROSING.

WILLIAM C. STEVENS. 

